Almost every semen sample contains cells other than spermatozoa. These may be polygonal cells from the genital tract, but mostly they are nucleated round cells. Round cells are either spermatogenetic precursor cells (spermatids, spermatocytes, sometimes spermatogonia) or white blood cells. Amongst the latter, lymphocytes are rather uncommon, and the majority are polymorphonuclear granulocytes, characterized by granules containing the enzyme peroxidase.
LeucoScreen Plus is an improved histochemical staining kit for the determination of peroxidase-positive white blood cells in semen. The kit provides useful information in semen samples where the concentration of round cells exceeds 1 million/ml. LeucoScreen Plus has an equal capability to distinguish between peroxidase-positive and -negative round cells as the LeucoScreen kit (same assay performance), but has the advantage that the substrate is not carcinogenic. The color of the substrate in peroxidase-positive white blood cells is bluish-grey to black instead of brown (LeucoScreen). The kit has been designed for 40 days of analysis.
LeucoScreen Plus has a 12 month shelf life from date of produce. Information about the composition of the product can be found in the material safety data sheet.